The Whites Matrix M6 is a "easy-to-use coin and jewelry detector for parks, beaches and general use in all ground conditions". Some of the Matrix M6's features include 2 controls, pinpoint and all metal mode, 7 tone id, full size display, and a 9.5 inch waterproof search coil. I've also read the opinion in multiple places that the Matrix M6 is the little brother to the Whites MXT having only two knobs and doesn't have a relic or prospecting mode like the MXT, so the M6 is geared toward the coin and jewelry consumers (It's also a couple hundred dollars cheaper).

Steve over at Findmall has an article on the Matrix M6 discussing his first impressions of the metal detector. They like the Matrix M6 for coin and jewelry hunting and offer their interpretation of the M6's audio tones and respective frequencies. They also consider the audio to be a step up from the MXT, and like the optional automatic ground balancing. In conclusion they offer White's a tip on how to make the Matrix M6 a truly phenomenal detector.

Web pages on the Matrix M6 are hard to come by so here's the White's page on the M6. You'll find a few pictures of the M6 there and also details on the M6's two year warranty. Additionally in the right margin you can find some recommended accessories for the Matrix M6 and explore all of the White's detector lineup from the left column.